//#include "stdafx.h"
#include "md_5.h"

using namespace std;

/* Constants for MD5Transform routine. */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

#define BUFFER_SIZE 10240
/* F, G, H and I are basic MD5 functions.
*/
#define F( x, y, z ) ( ( ( x ) & ( y ) ) | ( ( ~x ) & ( z ) ) )
#define G( x, y, z ) ( ( ( x ) & ( z ) ) | ( ( y ) & ( ~z ) ) )
#define H( x, y, z ) ( ( x ) ^ ( y ) ^ ( z ) )
#define I( x, y, z ) ( ( y ) ^ ( ( x ) | ( ~z ) ) )

/* ROTATE_LEFT rotates x left n bits.
*/
#define ROTATE_LEFT( x, n ) ( ( ( x ) << ( n ) ) | ( ( x ) >> ( 32-( n ) ) ) )

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#define FF( a, b, c, d, x, s, ac ) { \
	( a ) += F ( ( b ), ( c ), ( d ) ) + ( x ) + ac; \
	( a ) = ROTATE_LEFT ( ( a ), ( s ) ); \
	( a ) += ( b ); \
}
#define GG( a, b, c, d, x, s, ac ) { \
	( a ) += G ( ( b ), ( c ), ( d ) ) + ( x ) + ac; \
	( a ) = ROTATE_LEFT ( ( a ), ( s ) ); \
	( a ) += ( b ); \
}
#define HH( a, b, c, d, x, s, ac ) { \
	( a ) += H ( ( b ), ( c ), ( d ) ) + ( x ) + ac; \
	( a ) = ROTATE_LEFT ( ( a ), ( s ) ); \
	( a ) += ( b ); \
}
#define II( a, b, c, d, x, s, ac ) { \
	( a ) += I ( ( b ), ( c ), ( d ) ) + ( x ) + ac; \
	( a ) = ROTATE_LEFT ( ( a ), ( s ) ); \
	( a ) += ( b ); \
}


const byte MD5::PADDING[64] = { 0x80 };

const char_t MD5::HEX[16] = 
{
	_T('0'), _T('1'), _T('2'), _T('3'),
	_T('4'), _T('5'), _T('6'), _T('7'),
	_T('8'), _T('9'), _T('a'), _T('b'),
	_T('c'), _T('d'), _T('e'), _T('f')
};

/* Default construct. */
MD5::MD5( ) 
{
	reset( );
}

/* Construct a MD5 object with a input buffer. */
MD5::MD5( const void *input, size_t length )
{
	reset( );
	update( input, length );
}

/* Construct a MD5 object with a string. */
MD5::MD5( const string &str ) 
{
	reset( );
	update( str );
}

/* Construct a MD5 object with a file. */
MD5::MD5( ifstream &in )
{
	reset( );
	update( in );
}

/* Return the message-digest */
const byte* MD5::digest( )
{
	if ( !_finished ) 
	{
		_finished = true;
		final( );
	}

	return _digest;
}

/* Reset the calculate state */
void MD5::reset( ) 
{

	_finished = false;
	/* reset number of bits. */
	_count[0] = _count[1] = 0;
	/* Load magic initialization constants. */
	_state[0] = 0x67452301;
	_state[1] = 0xefcdab89;
	_state[2] = 0x98badcfe;
	_state[3] = 0x10325476;
}

/* Updating the context with a input buffer. */
void MD5::update( const void *input, size_t length ) 
{
	update( ( const byte* )input, length );
}

/* Updating the context with a string. */
void MD5::update( const string &str )
{
	update( ( const byte* )str.c_str( ), str.length( ) );
}

/* Updating the context with a file. */
void MD5::update( ifstream &in ) 
{

	if ( !in )
	{
		return;
	}

	std::streamsize length;
	char buffer[BUFFER_SIZE] = {'\0'};

	while ( !in.eof( ) ) 
	{
		in.read( buffer, BUFFER_SIZE );
		length = in.gcount( );

		if ( length > 0 )
		{
			update( buffer, length );
		}
	}

	in.close( );
}

/* MD5 block update operation. Continues an MD5 message-digest
operation, processing another message block, and updating the
context.
*/
void MD5::update( const byte *input, size_t length ) 
{

	ulong i, index, partLen;

	_finished = false;

	/* Compute number of bytes mod 64 */
	index = ( ulong )( ( _count[0] >> 3 ) & 0x3f );

	/* update number of bits */
	if( ( _count[0] += ( ( ulong )length << 3 ) ) < ( ( ulong )length << 3 ) )
	{
		_count[1]++;
	}

	_count[1] += ( ( ulong )length >> 29 );

	partLen = 64 - index;

	/* transform as many times as possible. */
	if( length >= partLen )
	{

		memcpy( &_buffer[index], input, partLen );
		transform( _buffer );

		for ( i = partLen; i + 63 < length; i += 64 )
		{
			transform( &input[i] );
		}

		index = 0;

	}
	else 
	{
		i = 0;
	}

	/* Buffer remaining input */
	memcpy( &_buffer[index], &input[i], length-i );
}

/* MD5 finalization. Ends an MD5 message-_digest operation, writing the
the message _digest and zeroizing the context.
*/
void MD5::final( ) 
{

	byte bits[8];
	ulong oldState[4];
	ulong oldCount[2];
	ulong index, padLen;

	/* Save current state and count. */
	memcpy( oldState, _state, 16 );
	memcpy( oldCount, _count, 8 );

	/* Save number of bits */
	encode( _count, bits, 8 );

	/* Pad out to 56 mod 64. */
	index = ( ulong )( ( _count[0] >> 3 ) & 0x3f );
	padLen = ( index < 56 ) ? ( 56 - index ) : ( 120 - index );
	update( PADDING, padLen );

	/* Append length ( before padding ) */
	update( bits, 8 );

	/* Store state in digest */
	encode( _state, _digest, 16 );

	/* Restore current state and count. */
	memcpy( _state, oldState, 16 );
	memcpy( _count, oldCount, 8 );
}

/* MD5 basic transformation. Transforms _state based on block. */
void MD5::transform( const byte block[64] ) 
{

	ulong a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16];

	decode( block, x, 64 );

	/* Round 1 */
	FF ( a, b, c, d, x[ 0], S11, 0xd76aa478 ); /* 1 */
	FF ( d, a, b, c, x[ 1], S12, 0xe8c7b756 ); /* 2 */
	FF ( c, d, a, b, x[ 2], S13, 0x242070db ); /* 3 */
	FF ( b, c, d, a, x[ 3], S14, 0xc1bdceee ); /* 4 */
	FF ( a, b, c, d, x[ 4], S11, 0xf57c0faf ); /* 5 */
	FF ( d, a, b, c, x[ 5], S12, 0x4787c62a ); /* 6 */
	FF ( c, d, a, b, x[ 6], S13, 0xa8304613 ); /* 7 */
	FF ( b, c, d, a, x[ 7], S14, 0xfd469501 ); /* 8 */
	FF ( a, b, c, d, x[ 8], S11, 0x698098d8 ); /* 9 */
	FF ( d, a, b, c, x[ 9], S12, 0x8b44f7af ); /* 10 */
	FF ( c, d, a, b, x[10], S13, 0xffff5bb1 ); /* 11 */
	FF ( b, c, d, a, x[11], S14, 0x895cd7be ); /* 12 */
	FF ( a, b, c, d, x[12], S11, 0x6b901122 ); /* 13 */
	FF ( d, a, b, c, x[13], S12, 0xfd987193 ); /* 14 */
	FF ( c, d, a, b, x[14], S13, 0xa679438e ); /* 15 */
	FF ( b, c, d, a, x[15], S14, 0x49b40821 ); /* 16 */

	/* Round 2 */
	GG ( a, b, c, d, x[ 1], S21, 0xf61e2562 ); /* 17 */
	GG ( d, a, b, c, x[ 6], S22, 0xc040b340 ); /* 18 */
	GG ( c, d, a, b, x[11], S23, 0x265e5a51 ); /* 19 */
	GG ( b, c, d, a, x[ 0], S24, 0xe9b6c7aa ); /* 20 */
	GG ( a, b, c, d, x[ 5], S21, 0xd62f105d ); /* 21 */
	GG ( d, a, b, c, x[10], S22,  0x2441453 ); /* 22 */
	GG ( c, d, a, b, x[15], S23, 0xd8a1e681 ); /* 23 */
	GG ( b, c, d, a, x[ 4], S24, 0xe7d3fbc8 ); /* 24 */
	GG ( a, b, c, d, x[ 9], S21, 0x21e1cde6 ); /* 25 */
	GG ( d, a, b, c, x[14], S22, 0xc33707d6 ); /* 26 */
	GG ( c, d, a, b, x[ 3], S23, 0xf4d50d87 ); /* 27 */
	GG ( b, c, d, a, x[ 8], S24, 0x455a14ed ); /* 28 */
	GG ( a, b, c, d, x[13], S21, 0xa9e3e905 ); /* 29 */
	GG ( d, a, b, c, x[ 2], S22, 0xfcefa3f8 ); /* 30 */
	GG ( c, d, a, b, x[ 7], S23, 0x676f02d9 ); /* 31 */
	GG ( b, c, d, a, x[12], S24, 0x8d2a4c8a ); /* 32 */

	/* Round 3 */
	HH ( a, b, c, d, x[ 5], S31, 0xfffa3942 ); /* 33 */
	HH ( d, a, b, c, x[ 8], S32, 0x8771f681 ); /* 34 */
	HH ( c, d, a, b, x[11], S33, 0x6d9d6122 ); /* 35 */
	HH ( b, c, d, a, x[14], S34, 0xfde5380c ); /* 36 */
	HH ( a, b, c, d, x[ 1], S31, 0xa4beea44 ); /* 37 */
	HH ( d, a, b, c, x[ 4], S32, 0x4bdecfa9 ); /* 38 */
	HH ( c, d, a, b, x[ 7], S33, 0xf6bb4b60 ); /* 39 */
	HH ( b, c, d, a, x[10], S34, 0xbebfbc70 ); /* 40 */
	HH ( a, b, c, d, x[13], S31, 0x289b7ec6 ); /* 41 */
	HH ( d, a, b, c, x[ 0], S32, 0xeaa127fa ); /* 42 */
	HH ( c, d, a, b, x[ 3], S33, 0xd4ef3085 ); /* 43 */
	HH ( b, c, d, a, x[ 6], S34,  0x4881d05 ); /* 44 */
	HH ( a, b, c, d, x[ 9], S31, 0xd9d4d039 ); /* 45 */
	HH ( d, a, b, c, x[12], S32, 0xe6db99e5 ); /* 46 */
	HH ( c, d, a, b, x[15], S33, 0x1fa27cf8 ); /* 47 */
	HH ( b, c, d, a, x[ 2], S34, 0xc4ac5665 ); /* 48 */

	/* Round 4 */
	II ( a, b, c, d, x[ 0], S41, 0xf4292244 ); /* 49 */
	II ( d, a, b, c, x[ 7], S42, 0x432aff97 ); /* 50 */
	II ( c, d, a, b, x[14], S43, 0xab9423a7 ); /* 51 */
	II ( b, c, d, a, x[ 5], S44, 0xfc93a039 ); /* 52 */
	II ( a, b, c, d, x[12], S41, 0x655b59c3 ); /* 53 */
	II ( d, a, b, c, x[ 3], S42, 0x8f0ccc92 ); /* 54 */
	II ( c, d, a, b, x[10], S43, 0xffeff47d ); /* 55 */
	II ( b, c, d, a, x[ 1], S44, 0x85845dd1 ); /* 56 */
	II ( a, b, c, d, x[ 8], S41, 0x6fa87e4f ); /* 57 */
	II ( d, a, b, c, x[15], S42, 0xfe2ce6e0 ); /* 58 */
	II ( c, d, a, b, x[ 6], S43, 0xa3014314 ); /* 59 */
	II ( b, c, d, a, x[13], S44, 0x4e0811a1 ); /* 60 */
	II ( a, b, c, d, x[ 4], S41, 0xf7537e82 ); /* 61 */
	II ( d, a, b, c, x[11], S42, 0xbd3af235 ); /* 62 */
	II ( c, d, a, b, x[ 2], S43, 0x2ad7d2bb ); /* 63 */
	II ( b, c, d, a, x[ 9], S44, 0xeb86d391 ); /* 64 */

	_state[0] += a;
	_state[1] += b;
	_state[2] += c;
	_state[3] += d;
}

/* Encodes input ( ulong ) into output ( byte ). Assumes length is
a multiple of 4.
*/
void MD5::encode( const ulong *input, byte *output, size_t length )
{

	for( size_t i=0, j=0; j<length; i++, j+=4 )
	{
		output[j]= ( byte )( input[i] & 0xff );
		output[j+1] = ( byte )( ( input[i] >> 8 ) & 0xff );
		output[j+2] = ( byte )( ( input[i] >> 16 ) & 0xff );
		output[j+3] = ( byte )( ( input[i] >> 24 ) & 0xff );
	}
}

/* Decodes input ( byte ) into output ( ulong ). Assumes length is
a multiple of 4.
*/
void MD5::decode( const byte *input, ulong *output, size_t length )
{

	for( size_t i=0, j=0; j<length; i++, j+=4 ) 
	{	
		output[i] = ( ( ulong )input[j] ) | ( ( ( ulong )input[j+1] ) << 8 ) |
			( ( ( ulong )input[j+2] ) << 16 ) | ( ( ( ulong )input[j+3] ) << 24 );
	}
}

/* Convert byte array to hex string. */
string_t MD5::bytesToHexString( const byte *input, size_t length )
{
	string_t str;
	str.reserve( length << 1 );

	for( size_t i = 0; i < length; i++ ) 
	{
		int t = input[i];
		int a = t / 16;
		int b = t % 16;
		str.append( 1, HEX[a] );
		str.append( 1, HEX[b] );
	}

	return str;
}
size_t MD5::HexStringToBytes( const byte * input, size_t in_len, byte * output, size_t out_len )
{
	size_t nCount = 0;
	for( size_t i = 0, j = 0; i + 1 < in_len && j < out_len; i += 2, j++ )
	{
		output[j] = input[i]*16 + input[i+1];
		nCount++;
	}
	return nCount;
}
/* Convert digest to string value */
string_t MD5::toString( ) 
{
	return bytesToHexString( digest( ), 16 );
}